import urllib, re
a ='http\x3a\x2f\x2fcid-e4554d9119fbda1e.skydrive.live.com\x2fself.aspx\x2f.Public\x2fchicks\x257C_small.png'

reDown = re.compile(r"_download\s*=\s*'(?P<url>[^']+)",re.I|re.M)
a="""

var _download = 'http\x3a\x2f\x2fa7s1lg.bay.livefilestore.com\x2fy1pSd1HbbS5K_gXkd3FJXhRZnTKkOpn1Clz8cVa-pI6cLZdz55tDmqQ6eNvp-mhx2IlsfaOT1NCarM\x2fchicks_small.png\x3fdownload';

"""
#for m in reDown.finditer(a): 
#    print m.groups()
print reDown.search(a).group('url')
